Gas strainer



Sept. 11, 1962 s, YOUNG GAS STRAINER Filed July 10, 1958 6 M .W H UK NYm M in mM w W A M R M am F United States Patent Ofiice 3,053,032Patented Sept. 11, 1962 3,053,032 GAS STRAINER Farrile S. Young,Houston, Tex., assignor to Gulf Interstate Oil Company, Houston, Tex., acorporation of Delaware Filed July 10, 1959, Ser. No. 747,782 4 Claims.(61. 55416) This invention relates to strainers and more particularly tostrainers for gas transmission lines.

Gas is transmitted across a country in large diameter pipes under highpressure. It is necessary to repressure the gas en route and for thispurpose, compressor stations are located at spaced points along theline. The cost of equipment and operation of these compressor stationsis high. Therefore, impediments in the line which cause a substantialdrop in pressure are not tolerated, as this pressure drop must bereplaced by the compressors.

Conventional strainers cause appreciable pressure drops and, therefore,are not employed in gas transmission lines. Some means of removingforeign matter in gas transmission lines is needed. Large solids such ascoupons, welding beads, etc. can find their way into compressors andruin expensive equipment. Small solid particles and condensate may passcompressor stations but will eventually fall out in the line and reduceits effective diameter.

It is an object of this invention to provide a strainer for use in gastransmission lines which will cause only a negligible pressure drop.

Another object of this invention is to provide a strainer for use in gastransmission lines which will cause only a negligible pressure drop andwhich will remove both large and small particles as well as condensatein the line.

Another object is to provide a strainer which will strain out entrainedsmall particles and condensate which pass through the opening in thestrainer employed.

Other objects, features and advantages of this invention will beapparent from the specification, the drawing and the claims.

In accordance with this invention, the strainer is provided with a platewhich spans the pipeline, and a large number of venturi openings areprovided in the plate. Due to the well known venturi action, it ispossible to strain the gas without substantially reducing its pressure.Preferably the plate having the venturi openings is inclined at an acuteangle to the direction of flow which causes the gas to change directionsas it passes through the plate. Thereafter, the gas is straightened outand resumes its original flow direction. However, the more dense solidsand entrained liquids which are carried by the gas will continue in thechanged direction due to their greater mass and inertia. In this mannerthey are directed against the bottom of the pipe and into a sump wherethey are collected for periodic straining.

Referring now to the drawings wherein there is shown an illustrativeembodiment of this invention:

FIGURE 1 is a side elevation of a pipeline equipped with a strainerconstructed in accordance with this invention;

FIGURE 2 is a view on an enlarged scale partially in side elevation andpartially in vertical cross section illustrating the strainer shown inFIGURE 1; and

FIGURE 3 is a view in side elevation of one of the strainer platesemployed in the strainer of FIGURES 1 and 2.

Referring now to the drawings, the strainer includes a body made up ofthe tubular members and 11, which are secured together in alignedrelationship as by welding in the conventional manner. A one-piece bodycould be used if desired but a two-piece body permits better access tothe interior of the body portion 10. The strainer body is secured in thepipeline 12 as by welding in the conventional manner.

The body section 10 is provided with a sump 13 for trapping smallparticles of solid matter and for collecting liquid knocked out of thegas stream by the strainer. This sump includes a manhole 14 closed by alid 15 to permit cleaning out of the sump and access to the interior ofthe body member 10.

For ease of cleaning the sump 13, a pipe 16 is provided in the closuremember 15. This pipe is controlled by valve 17 and opening of the valvewill permit the gas pressure within the line to blow the accumulatedliquid and small particles within the sump out through line 16. It iscontemplated that this will be done at periodic intervals.

A strainer plate 18 is secured across the opening through the tubularbody 10 on the upstream side of sump 13. This plate is preferablysecured in place by welding it to the internal wall of the tubular body10. Preferably the plate is inclined so that the upper end of the plateis downstream from the lower end. In other words, the most downstreamend of the plate 18 is on the opposite side of the body 10 from the sump13. By inclining the plate 18, its total area is increased.

Provision is made for gas and small entrained particles and condensateto pass through the plate 18 by a plurality of small venturi openings19. These venturi openings function in the usual way to permit passageof fluid at increased velocity and reduced pressure and permit therecovery of substantially all of the reduced pres sure after the gas haspassed through the venturi. These venturi openings are suificientlysmall that large particles of solids, such as welding beads, coupons andthe like, will fall into the tubular body section 11 in front of thestrainer plate 18. This will prevent large size foreign matter frompassing through the pipe and entering compressors and other equipmentwhich can be damaged by the solids. Preferably the body section 11 isprovided with a cleanout manhole 21 to permit removal of these largeparticles of foreign matter.

To assist in removing small particles which pass through the venturiopenings 19 and entrained liquid, the central axes of the venturiopenings are inclined downwardly toward sump 14. Thus, as an entrainedparticle passes through a venturi opening 19, its velocity is increaseddue to the venturi action. After leaving the strainer plate 18, the gasincreases in pressure and reduces in velocity. However, the inertia ofthe entrained particles and condensate will cause these particles totend to continue in the downward path toward the sump even though thegas is straightened out and continued on down the line. This action isdemonstrated by line 22 which represents gas passing on through the lineand the particle trails 23 of particle 24 and particle trail 25 ofparticle 26. It Will be appreciated that with this arrangement smallsolids and entrained liquids which are too small to be removed with astrainer can be removed from the gas stream.

After the gas has passed through the strainer plate 18, it is desirableto straighten out the gas stream while permitting the inertia of theentrained particles to carry them to the bottom of the pipe. This may beaccomplished by any suitable mechanism which will provide straighteningvanes and cause the gas to flow in the general manner shown by gastrails 22., 27 and 28. Preferably the straightening vane is provided bya second plate 29 which has a plurality of venturi openings 31therethrough. Preferably this plate 29 is inclined in opposite manner tothe plate 18, and the venturi openings are also inclined in oppositemanner to the venturi openings 19 of plate 18. This arrangement willstraighten out the gas flow and reduce turbulence of the gas to therebyreduce pressure drop caused by the strainer. Of course the second screenwill also act as a strainer and tend to strain out any small particleswhich have not previously been removed from the gas stream.

The foregoing disclosure and description of the inven tion isillustrative and explanatory thereof and various changes in the size,shape and materials, as well as in the details of the illustratedconstruction, may be made Within the scope of the appended claimswithout departing from the spirit of the invention.

What is claimed is:

1. A gas strainer comprising, a tubular body adapted to be made up in apipeline, a sump in the body for colleeting foreign matter, a strainerplate extending across the body upstream of the sump, and a plurality ofventuri openings in the plate having their central axes inclined towardthe sump.

2. The strainer of claim 1 wherein a cleanout manhole is providedupstream of the plate to permit removal of foreign matter which does notpass through the plate.

3. A gas strainer comprising, a tubular body adapted to be made up in apipeline, a sump in the body for collecting foreign matter, a strainerplate extending across the body upstream of the sump, a plurality ofventuri openings in the plate having their central axes inclined towardthe sump, and means downstream of the plate for straightening out thegas flow.

4. A gas strainer comprising, a tubular body adapted to be made up in apipeline, a sump in the body for collecting foreign matter, a firststrainer plate extending across the body with its top positioneddownstream from its bottom to provide an inclined plate, a plurality ofventuri openings in the plate having their central axes inclined towardsaid sump, a second strainer plate positioned downstream of the sump andinclined in opposite manner to the first strainer plate, a plurality ofventuri openings in the second plate inclined in opposite manner to theopenings in the first plate, and a manhole upstream of the first plateto permit removal of foreign matter which does not pass through theplate.

References Cited in the file of this patent UNITED STATES PATENTS1,593,221 Ranyard July 20, 1926 2,178,240 Pascale Oct. 31, 19392,246,994 Herbster June 24, 194i FOREIGN PATENTS 526,363 Ger-many June5, 1931

